event.c revision 281210 
1/*
2 * event.h
3 */
4
5/*-
6 * Copyright (c) 2009 Maksim Yevmenkin <m_evmenkin@yahoo.com>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31/* $FreeBSD: head/usr.sbin/bluetooth/btpand/event.c 281210 2015-04-07 16:48:23Z takawata $ */
32
33/*
34 * Hack to provide libevent (see devel/libevent port) like API.
35 * Should be removed if FreeBSD ever decides to import libevent into base.
36 */
37
38#include <sys/select.h>
39#include <sys/time.h>
40#include <sys/queue.h>
41#include <assert.h>
42#include <stdarg.h>
43#include <stdio.h>
44#include <string.h>
45#include <syslog.h>
46
47#include "event.h"
48#define L2CAP_SOCKET_CHECKED
49#include "btpand.h"
50
51#define		__event_link(ev) \
52do { \
53		TAILQ_INSERT_TAIL(&pending, ev, next); \
54		ev->flags |= EV_PENDING; \
55} while (0)
56
57static void	tv_add(struct timeval *, struct timeval const *);
58static void	tv_sub(struct timeval *, struct timeval const *);
59static int	tv_cmp(struct timeval const *, struct timeval const *);
60static int	__event_dispatch(void);
61static void	__event_add_current(struct event *);
62static void	__event_del_current(struct event *);
63
64
65static TAILQ_HEAD(, event)	pending;
66static TAILQ_HEAD(, event)	current;
67
68void
69event_init(void)
70{
71	TAILQ_INIT(&pending);
72}
73
74int
75event_dispatch(void)
76{
77	while (__event_dispatch() == 0)
78		;
79
80	return (-1);
81}
82
83static int
84__event_dispatch(void)
85{
86	fd_set			r, w;
87	int			nfd;
88	struct event		*ev;
89	struct timeval		now, timeout, t;
90
91	FD_ZERO(&r);
92	FD_ZERO(&w);
93
94	nfd = 0;
95
96	gettimeofday(&now, NULL);
97
98	timeout.tv_sec = 10;	/* arbitrary */
99	timeout.tv_usec = 0;
100
101	TAILQ_INIT(&current);
102
103	/*
104	 * Build fd_set's
105	 */
106
107	event_log_debug("%s: building fd set...", __func__);
108
109	while (!TAILQ_EMPTY(&pending)) {
110		ev = TAILQ_FIRST(&pending);
111		event_del(ev);
112
113		if (ev->flags & EV_HAS_TIMEOUT) {
114			if (tv_cmp(&now, &ev->expire) >= 0)
115				t.tv_sec = t.tv_usec = 0;
116			else {
117				t = ev->expire;
118				tv_sub(&t, &now);
119			}
120
121			if (tv_cmp(&t, &timeout) < 0)
122				timeout = t;
123		}
124
125		if (ev->fd >= 0) {
126			if (ev->flags & EV_READ) {
127				FD_SET(ev->fd, &r);
128				nfd = (nfd > ev->fd) ? nfd : ev->fd;
129			}
130
131			if (ev->flags & EV_WRITE) {
132				FD_SET(ev->fd, &w);
133				nfd = (nfd > ev->fd) ? nfd : ev->fd;
134			}
135		}
136
137		__event_add_current(ev);
138	}
139
140	event_log_debug("%s: waiting for events...", __func__);
141
142	nfd = select(nfd + 1, &r, &w, NULL, &timeout);
143	if (nfd < 0)
144		return (-1);
145
146	/*
147	 * Process current pending
148	 */
149
150	event_log_debug("%s: processing events...", __func__);
151
152	gettimeofday(&now, NULL);
153
154	while (!TAILQ_EMPTY(&current)) {
155		ev = TAILQ_FIRST(&current);
156		__event_del_current(ev);
157
158		/* check if fd is ready for reading/writing */
159		if (nfd > 0 && ev->fd >= 0) {
160			if (FD_ISSET(ev->fd, &r) || FD_ISSET(ev->fd, &w)) {
161				if (ev->flags & EV_PERSIST) {
162					if (ev->flags & EV_HAS_TIMEOUT)
163						event_add(ev, &ev->timeout);
164					else
165						event_add(ev, NULL);
166				}
167
168				nfd --;
169
170				event_log_debug("%s: calling %p(%d, %p), " \
171					"ev=%p", __func__, ev->cb, ev->fd,
172					ev->cbarg, ev);
173
174				(ev->cb)(ev->fd,
175					(ev->flags & (EV_READ|EV_WRITE)),
176					ev->cbarg);
177
178				continue;
179			}
180		}
181
182		/* if event has no timeout - just requeue */
183		if ((ev->flags & EV_HAS_TIMEOUT) == 0) {
184			event_add(ev, NULL);
185			continue;
186		}
187
188		/* check if event has expired */
189		if (tv_cmp(&now, &ev->expire) >= 0) {
190			if (ev->flags & EV_PERSIST)
191				event_add(ev, &ev->timeout);
192
193			event_log_debug("%s: calling %p(%d, %p), ev=%p",
194				__func__, ev->cb, ev->fd, ev->cbarg, ev);
195
196			(ev->cb)(ev->fd,
197				(ev->flags & (EV_READ|EV_WRITE)),
198				ev->cbarg);
199
200			continue;
201		}
202
203		assert((ev->flags & (EV_PENDING|EV_CURRENT)) == 0);
204		__event_link(ev);
205	}
206
207	return (0);
208}
209
210void
211__event_set(struct event *ev, int fd, short flags,
212	void (*cb)(int, short, void *), void *cbarg)
213{
214	ev->fd = fd;
215	ev->flags = flags;
216	ev->cb = cb;
217	ev->cbarg = cbarg;
218}
219
220int
221__event_add(struct event *ev, const struct timeval *timeout)
222{
223	assert((ev->flags & (EV_PENDING|EV_CURRENT)) == 0);
224
225	if (timeout != NULL) {
226		gettimeofday(&ev->expire, NULL);
227		tv_add(&ev->expire, timeout);
228		ev->timeout = *timeout;
229		ev->flags |= EV_HAS_TIMEOUT;
230	} else
231		ev->flags &= ~EV_HAS_TIMEOUT;
232
233	__event_link(ev);
234
235	return (0);
236}
237
238int
239__event_del(struct event *ev)
240{
241	assert((ev->flags & EV_CURRENT) == 0);
242
243	if ((ev->flags & EV_PENDING) != 0) {
244		TAILQ_REMOVE(&pending, ev, next);
245		ev->flags &= ~EV_PENDING;
246	}
247
248	return (0);
249}
250
251static void
252__event_add_current(struct event *ev)
253{
254	assert((ev->flags & (EV_PENDING|EV_CURRENT)) == 0);
255
256	TAILQ_INSERT_TAIL(&current, ev, next);
257	ev->flags |= EV_CURRENT;
258}
259
260static void
261__event_del_current(struct event *ev)
262{
263	assert((ev->flags & (EV_CURRENT|EV_PENDING)) == EV_CURRENT);
264
265	TAILQ_REMOVE(&current, ev, next);
266	ev->flags &= ~EV_CURRENT;
267}
268
269static void
270tv_add(struct timeval *a, struct timeval const *b)
271{
272	a->tv_sec += b->tv_sec;
273	a->tv_usec += b->tv_usec;
274
275	if(a->tv_usec >= 1000000) {
276		a->tv_usec -= 1000000;
277		a->tv_sec += 1;
278	}
279}
280
281static void
282tv_sub(struct timeval *a, struct timeval const *b)
283{
284	if (a->tv_usec < b->tv_usec) {
285		a->tv_usec += 1000000;
286		a->tv_sec -= 1;
287	}
288
289	a->tv_usec -= b->tv_usec;
290	a->tv_sec -= b->tv_sec;
291}
292
293static int
294tv_cmp(struct timeval const *a, struct timeval const *b)
295{
296 	if (a->tv_sec > b->tv_sec)
297		return (1);
298
299	if (a->tv_sec < b->tv_sec)
300		return (-1);
301
302	if (a->tv_usec > b->tv_usec)
303		return (1);
304
305	if (a->tv_usec < b->tv_usec)
306		return (-1);
307
308	return (0);
309}
310
311